How to pass text from tableViewCell a tableView header on another viewController

I am failing to pass the text from the label in the cell on the FirstVC to a label in the tableView header on the SecondVC.

You can see what I get in the attached screenshot.

Also, once this question is resolved, I feel like I will need to deal with the header height (it should be dynamically adjusted to the size of the label. But I think this should be done in a separate question on SO.

Here's my FirstVC:

import UIKit

class FirstVC: UIViewController, UITableViewDelegate, UITableViewDataSource {
    
    @IBOutlet weak var firstTableView: UITableView!
    
    var people: [FirstTVCellModel] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        firstTableView.delegate = self
        firstTableView.dataSource = self
        
        people = [
            FirstTVCellModel(userNameModel: "This text should appear in the label in the header of the tableView on a SecondVC. Here, let's say it would be a user's name (like Seth Brown). In the real project, the text will be added here from a third static tableView with text fields through the unwindToFirstVC segue. Hope it makes sense", dateModel: Date(timeIntervalSinceNow: -5615416)),
            FirstTVCellModel(userNameModel: "Person 2", dateModel: Date(timeIntervalSinceNow: -5615416)),
            FirstTVCellModel(userNameModel: "Person 3", dateModel: Date(timeIntervalSinceNow: -5615416))
        ]
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        people.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = firstTableView.dequeueReusableCell(withIdentifier: "FirstTVCell", for: indexPath) as! FirstTVCell
        let Person = people[indexPath.row]
        cell.userNameLabel.text = Person.userNameModel
        cell.dateLabel.text = Person.formattedDate
        return cell
    }
    
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        firstTableView.deselectRow(at: indexPath, animated: true)
        if let vc = storyboard?.instantiateViewController(withIdentifier: "SecondVC") as? SecondVC {
            self.navigationController?.pushViewController(vc, animated: true)
        }
    }
}

And this is my Second VC:

import UIKit

class SecondVC: UIViewController, UITableViewDelegate, UITableViewDataSource {
    
    @IBOutlet weak var secondTableView: UITableView!
    
    var stuff = [("Some other stuff 1"),("Some other stuff 2"),("Some other stuff 3")]
    
    var insertionText = FirstTVCellModel(userNameModel: "", dateModel: .none)

    override func viewDidLoad() {
        super.viewDidLoad()
        secondTableView.delegate = self
        secondTableView.dataSource = self
        
        let tableHeader = UIView(frame: CGRect(x: 0, y: 0, width: view.frame.size.width, height: 80))
        secondTableView.tableHeaderView = tableHeader
        tableHeader.backgroundColor = .systemOrange
        
        let labelOne = UILabel(frame: tableHeader.bounds)
        labelOne.text = "USER:"
        tableHeader.addSubview(labelOne)
        
        labelOne.translatesAutoresizingMaskIntoConstraints = false
        labelOne.centerXAnchor.constraint(equalTo: tableHeader.centerXAnchor).isActive = true
        labelOne.topAnchor.constraint(equalTo: tableHeader.safeAreaLayoutGuide.topAnchor, constant: 11).isActive = true
        
        let labelTwo = UILabel(frame: tableHeader.bounds)
        labelTwo.text = "Inherited text here: \(insertionText)"
        tableHeader.addSubview(labelTwo)
        
        labelTwo.numberOfLines = 0
        labelTwo.textAlignment = .center
        
        labelTwo.translatesAutoresizingMaskIntoConstraints = false
        labelTwo.topAnchor.constraint(equalTo: labelOne.bottomAnchor, constant: 0).isActive = true
        labelTwo.leadingAnchor.constraint(equalTo: tableHeader.layoutMarginsGuide.leadingAnchor, constant: 0).isActive = true
        labelTwo.trailingAnchor.constraint(equalTo: tableHeader.layoutMarginsGuide.trailingAnchor, constant: 0).isActive = true


        
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        stuff.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = secondTableView.dequeueReusableCell(withIdentifier: "SecondTVCell", for: indexPath) as! SecondTVCell
        cell.someOtherStuffLabel.text = stuff[indexPath.row]
        return cell
    }
}

You need to inject the value you want into the destination VC.

So you will need somewhere in the second VC to hold that text, for example

class SecondVC: UIViewController, UITableViewDelegate, UITableViewDataSource {
  var title: String
  //...
}

Then in the your first VC's tableView(didSelectRowAt:) get the text from your data source and inject it into VC 2. You can use the indexPath's .row value to get the appropriate data entry.

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    firstTableView.deselectRow(at: indexPath, animated: true)
    if let vc = storyboard?.instantiateViewController(withIdentifier: "SecondVC") as? SecondVC {
       vc.title = people[indexPath.row].userNameModel
       self.navigationController?.pushViewController(vc, animated: true)
    }
}

then you can just use the title property when setting up VC2.